The largest concentration of the local immune system in the form of the nodular associations of the lymphoid tissue with the epithelium of the mucous membranes (tonsils, single lymphoid nodules and their aggregations, named Peyer’s patches) is located in the gut. The paper is aimed at the study of the quantitative and planimetric correlations between the Peyer’s patches and the area of the small intestine of white rats based on the visual assessment and comparative analysis of some metric values. The study was conducted on 60 white male rats, which were assigned into 2 groups of 30 animals: after the morning feeding (controls) and after a daily fasting. After the removal made in advance, the gut-associated complexes have been studied from the stomach to the cecum. The resulting experimental data have been processed on a personal computer using the EXCEL 2010 (Microsoft Excel Corp., USA) software. No significant difference in the diameter and length of the small intestine of white rats of the first and second groups was found. The total area of the small intestine wall in the control group ranged from 8666 mm2 to 20724 mm2, and from 8496 mm2 to 20573 mm2 in group II (after a daily fasting), ranking equally. Thickness parameters of the small intestine in two groups of animals were almost similar in its unchanged, within the limits of individual variability, longitudinal length. To conduct an accurate quantitative and planimetric analysis of the aggregated lymphoid nodules of the white rat’s small intestine, it was advisable to distinguish 3 groups, namely: small-, medium- and large-sized. Thus, their total number varies from 12 to 28 units. Among them 8 to 17 units (on the average of 12.60±0.400) were small-sized, 2 to 11 (5.800±0.500) were medium-sized, and the large ones were not always found. For example, in the studied samples, they were absent in 6 animals, whereas 1 to 5 units were presented in the rest of animals. The area of single small Peyer’s patches ranged from 1.570 to 9.800 mm2, and their total area was 64.90±2.900 mm2; the area of medium samples individually ranges from 10.60 to 27.50 mm2. Totally, they occupy an average area of 97.60±8.00 mm2. The same value of individual large aggregated nodules is between 31.40 and 60.40 mm2, which totally accounted on the average of 58.40±10.30 mm2. Thus, the average statistical value of the total areas of Peyer’s patches is 220.9±14.40 mm2, accounting for only 2% of the total area of the small intestine wall of white rats, not including single lymphoid nodules, not exceeding 1 mm.